They're back. Cicadas have returned to Greater Cincinnati, but the latest invasion is much smaller and not as noisy. In fact, you might not notice them at all.

Annual cicadas have begun emerging from the ground this month, and will continue to do so until September. Like the Brood X cicadas, which come out every 17 years, the annual cicadas can be found throughout the region, and in mid-Atlantic states.

But these cicadas are very different from their periodical cousins, who invaded Greater Cincinnati this summer with an army 5 billion strong.

Gene Kritsky, a cicada researcher and biology professor at the College of Mount St. Joseph in Delhi Township, estimated that several million annual cicadas will emerge in the region.

The annual bugs come with a different strategy for survival. Whereas periodical cicadas survive because of their vast numbers, annual cicadas are excellent flyers and rely on stealth to avoid becoming a meal for predators, which range from birds and squirrels to humans.

They also look different. Periodicals have orange wings and red eyes, whereas the annual bugs are green with black eyes, allowing them to fade into the background of the trees they use for mating.

The strong flying skills of the annual cicadas allow them to get into the trees more quickly.

"They get up in the shadows of the trees and you can't see them," Kritsky said.

There are some similarities. The males sing to attract their mate, and the female cuts tree branches to lay her eggs. The baby cicadas, or nymphs, drop to the ground and burrow underground, where they feed on liquid in roots, just like their periodical cousins.

And there won't be a stench because there won't be billions of dead bugs lying everywhere.